"Cybermen were always the monsters that scared me the most," said Doctor Who executive producer Steven Moffat. "Not just because they were an awesome military force, but because sometimes they could be sleek and silver and right behind you without you even knowing. And with one of the all-time classic monsters returning, and a script from one of our finest novelists, it's no surprise we have attracted such stellar names as Tamzin, Jason and Warwick."

The series returns on Dec. 25 with the Christmas special, followed in the spring by a run of eight episodes to complete the seventh season.